Electric Scooter
The scooter, my passion! After decades of neglect of the means of transportation ... (then called, in 50 years, "scooter"), we are now witnessing its revival: a craze for two-wheel vehicle s 'seizes children, of course, but also grown-ups, even the elderly. Everyone wants to try and run on roads, pavements, squares and other places where it is (more or less) possible!
Besides racing or speed slaloms are held at local and national levels. Otherwise we would not be surprised if, before long, someone organized competitions in the world!
However, scooters involved in these races, as well as ordinary commercial scooters are very different from our "scooter" half of the last century: most were built by the father of the user, based on two axes of wood hinged together on a single-sphere by two bearings.
Today, the scooter has become an industrial product, chromed steel or polished aluminum, it is well contoured, lightweight but robust and is no longer restricted to rogues.
Hence, no doubt, the evolution of the concept. There are now versions motor whose jobs are very diverse: they occur on the docks, in tourist villages, in airports and amusement parks. And indeed, the electric scooter is the ideal vehicle to move in such places: it is convenient, compact and allows you to browse without significant fatigue distances for a very low cost.
Unlike ordinary scooter, the scooter-electric technologies cocktail tight but, despite this, we can build it yourself: a person who, in addition to his passion for electronics, some knowledge of mechanics, can be launched without fear.
Our implementation
Given the interest in this type of material, we thought to propose the construction of an electric scooter. You will find in this ar ticle description of electronic circuits used, and the mechanical assembly. This building is accessible to all, provided you have the minimum tools required (in the mechanical field, of course, because, in terms of electronics, we consider that it is acquired).
Several items can be bought in specialist stores (eg, wheels, engine or the brake) while others (chassis, handlebars) are easily achieved in the metal tube.
As for the electrical / electronics, the scooter has an electric motor, a group of rechargeable batteries, a PWM controller and a battery charger. For our implementation, we used a DC motor of 180 W, 36 V running with a consumption of about 5 A. The power source consists of three lead-gel batteries (sealed) within 7 to 12 V Ah (standard for 36 V). A "reservoir" of this kind gives a range of almost 1 hour 30 thoroughly. If you moderate speed, it can exceed two hours. About the speed, we could verify that with a low load (30 to 50 kg) can reach 20 to 25 km / h while with a high load (80 to 100 kg) maximum speed reached 20 km / h.
Cruise control PWM
The circuit diagram
See Figure 1. The core system consists of the battery pack / motor / regulator, as seen in the pictures (eg, Figure 2), is set in the context of the scooter in order to reduce as much as possible from the centroid vehicle.
The cruise control circuit produces a PWM signal applied to the motor power. The duration positive pulses can be set between zero (0%) and value (referred to the duty cycle) of almost 100%. Practically, we apply a voltage to the motor from 0 to about 36 V and, therefore, the speed goes from zero to a maximum value. PWM control provides a constant torque with optimum performance, even at low revs, and a decent top speed.
Our circuit uses three voltage comparators that are part of the integrated circuit U1, an LM339 (see Figure 7a). The first (U1A) is a buffer to obtain a threshold voltage between two values appropriate to the control of the following stages.
The R2 and R6 trimmers adjust the minimum and maximum values for the rotation of the potentiometer P1 achieves a linearly increasing speed, the engine shut-down to maximum speed.
The following two comparators and two NAND gates with Schmitt trigger, is the pulse generator itself: the values of RC networks used determine a working frequency of about 5 to 6 kHz. The duty cycle changes according to the voltage on pin 13, according to the description above.
When the voltage varies, the operating frequency also changes slightly. The transistors T1 and T2 operate as drivers of small power and the signal output directly controls the trigger (gate) of N-channel power MOSFET, a RFG70N06 (see Figure 7b). This device can work under 60 V with a maximum current of 70 A: which is more than enough to meet our needs.
Power to the cruise control is entrusted to an integrated circuit regulator 12 V in series with a power resistor that is "fall" much of the difference between 36 and 12 V.
The complete circuit with the power MOSFET and the motor is activated by a relay: we used a double contact 24 V 10 A each.
In series with the coil of the relay we have planned, in addition to a ballast resistor (compensating for the difference in voltage), a key to start a general push normally closed (NC). The latter is attached to the brake lever to stop the motor when braking. Not only is the braking will be more effective but it will not damage the regulator or the PWM motor actions contrary.
Figure 1: Diagram of PWM speed control.
Figure 2: Our prototype electric motor scooter. Here, we have removed the fairing, allowing to see the group of three lead-gel batteries in series 36 V - 7 Ah ensuring autonomy of 30 km over 20 km / h.
Figure 3: View of our "chopper" or PWM speed control. FAST MOSFET and diode are mounted on a small aluminum heatsink.
Figure 4: Layout diagram of the components of PWM speed control.
Figure 5a: Photograph of a prototype of the PWM speed control. The installation of the speed controller has no particular difficulty.
The circuit uses a power MOSFET able to work under 60 V with a maximum current of 70 A: It can easily drive the DC motor 36 V 180 W.
Figure 5b: Schematic practice the beam from the handlebar controls. The potentiometer adjusts the speed. The circuit switching provides a normally closed pushbutton switch: the latter, under the brake lever, switch off the engine when you brake.
Figure 6: Drawing, scale 1, the circuit board PWM speed controller.
The circuit uses a power MOSFET able to work under 60 V with a maximum current of 70 A: It can easily drive the DC motor 36 V 180 W.
Figure 7: Pinout LM339 comparator, seen from above.
Figure 7b: Pin MOSFET RFG70N06.
List of components regulator
R1 = 1 k
R2 = 47 kOhms trimmer
R3 = 10 k
R4 = 33 kOhms
R5 = 270 kOhms
R6 = 1 MW trimmer
R7 = 330 kOhms
R8 = 2.2 MΩ
R9 = 2, 2 kW
R10 = 39 kOhms
R11 = 100 kOhms
R12 = 470 kOhms
R13 = 100 kOhms
R14 = 5.6 kOhms
R15 = 390 kOhms
R16 = 100 kOhms
R17 = 100 kOhms
R18 = 4.7 kOhms
R19 = 33 kOhms
R20 = 10 Ω
R21 = 470 Ω 2 W
R22 = 330 Ω 2 W
P1 = 2.2 kOhms pot. lin.
C1 = 100 nF multilayer
C2 = 10 uF 16 V electrolytic
C3 = 22 nF polyester
C4 = 47 nF polyester
C5 = 16 uF 470 V
electrolytic
C6 = 100 nF multilayer
C7 = 100 nF multilayer
C8 = 1000 pF ceramic
C9 = 470 uF 63 V electrolytic
D1 = 1N4148 Diode
Diode D2 = 1N4148
D3 = Diode BYW80-200
T1 = BC547B NPN
T2 = BC557B PNP
U1 = LM339 Integrated
U2 = Built 4093
Regulator U3 = 7812
MSFT1 = MOSFET RFG75N06
Relay RL1 = 24V 2 10 RT A
CH1 = Inter. Key
P1 Pusher NF =
M = Motor 180 W 36 V DC
Misc:
2 Supports 2 x 7-pin
1 TO220 Heatsink
An isolation kit for TO3P
An isolation kit for TO220
An aluminum bar (radiator)
4 FASTON Terminals for it
A 2-pole terminal block
1 3-pole
The practical realization
Refer to Figures 4 and 5a. As for mounting the controller, we have provided a printed circuit board visible figures 3, 5a and 6. The realization of this circuit can be made by the traditional system of photo-or the revolutionary process (and convenient) of the "blue film" (see ELM 26, page 59 et seq.)
The assembly itself presents no particular difficulty.
For the development of two integrated circuits we used two supports and two terminals for external connections, one for the pot and the other for the activation circuit (key and push). For connection to the engine and battery pack, since the currents involved, we have identified four male contacts FASTON PCB. The voltage regulator has a double sink fins for TO220. The power MOSFET and the diode FAST will also be equipped with a sink: it is an aluminum bar that serves small dimensions for both (do not forget to insulate the back of these components with insulation kits correspondents).
To check the operation of the PWM controller is recommended, as a first step, not to mount the MOSFET and control with an oscilloscope to the output of T1/T2 pulses are actually present positive variable duty cycle.
Adjust trimmers R2 and R6 to obtain a linear excursion of the potentiometer, that is to say no pulse when the cursor is turned fully on one side and pulse duty cycle of almost 100% when the cursor is in opposite position.
Only then insert the IC and connect the motor (set it on your work bench to prevent it jumps!). Connect the power supply and verify that the speed of rotation depends on the position of the potentiometer.
The battery charger
The circuit diagram
See Figure 8. The second electronic circuit used for our scooter battery charger is intended, of course, to charge the group of batteries from the mains 220 V.
The circuit we have developed uses (for AC / DC conversion) a PWM system to do without power transformer.
With the DC voltage obtained we reload the batteries and we check, using a suitable circuit, the charge state: when the batteries are charged, the circuit stops charging.
In our installation, the load is within 1 to 1.5 A current and is complete after about 5 hours.
But look more closely at the circuit.
AC voltage 220 V rectifier RS1 reached by a double LC filter eliminating the risk of disruption of the sector by spurious signals of the switching circuit.
Downstream of the bridge rectifier is a filter capacitor across which a voltage of 300 V is present. This voltage feeds directly into the power stage MOSFET MSFT1 leading to the transformer primary and TF1 (points 3 and 4).
The integrated circuit U1, a simple TL3842, belong all the functions for the PWM stage. In practice, this integrated circuit oscillates at a frequency of 57 kHz and produces a pulse train whose duty cycle depends on the consumption of the powered circuit: the greater the consumption of the circuit, the longer the pulse duration.
To check the circuit power consumption, simply measure the voltage drops across the resistance of low value placed in series with the source of the MOSFET: the tension acts on the internal comparator controlling the PWM generator.
This floor has two other features: power to the chip on and off the circuit by an optocoupler. The supply voltage is obtained from the 300 V DC through two ballast resistor providing current relatively low, just enough to start the chip and trigger the oscillation. Then the circuit is powered by the voltage on the winding TF1 (points 1 and 2).
This voltage, rectified by diode D1 and filtered by C7, adds to the initial tension, providing proper nutrition to chip.
As for the optocoupler is a component that, when active, can almost completely inhibit the operation of the PWM, or to minimize the amplitude of pulses produced.
It is worth noting that the high voltage stage is galvanically isolated from the low voltage level through the use of the transformer TF1 and the optocoupler.
Explained is how the presence of two distinct masses with different symbols (Figure 8).
The pulses present on the secondary TF1 (winding points 5 and 7) are recovered by the double diode D6 FAST and made perfectly continuous with the LC filter with L2 and C13 are a part. Across the capacitor, we find a normal voltage of 45 V used to recharge the batteries and to power the control circuit using four operational amplifiers contained in U2, a banal LM324. The green LED LD1 indicates that its ignition voltage is present on the side and then the whole floor upstream is working properly.
The integrated circuit LM324 is powered by a stabilized voltage of 28 V provided by Zener DZ2.
Another zener (DZ 1) provides the reference voltage operational amplifiers to function as voltage comparators.
To check the battery charge is measured current they consume. To this end was placed in series with batteries, a low value resistor whose voltage drop is compared to the reference voltage. When the load current drops below 100 mA, the LED signal LD2-color changes from red to green to indicate the end of the load. This is not interrupted: the battery is maintained "buffering".
This circuit consists of operational amplifiers U2B and U2c while the other two operational amplifiers are there to see if the battery is connected or not to the output terminals or if they are short-circuited. In both latter cases, the optocoupler is activated to limit the operation of the PWM. By trimmers R25 and R29, it is possible to adjust the thresholds of the circuit. The same goes for U2d (controlling the action level of short circuit) it is possible to make some sort of adjustment by removing R15, increasing the threshold.
Figure 8: Diagram of the battery charger.
Figure 9: Our platinum charger fully assembled.
Figure 10: Layout diagram of the components of the battery charger.
Figure 11: Photograph of a prototype of the battery charger.
Figure 12: Drawing on the scale 1, the circuit of the battery charger.
List of components regulator
R1 = 1 k
R2 = 47 kOhms trimmer
R3 = 10 k
R4 = 33 kOhms
R5 = 270 kOhms
R6 = 1 MW trimmer
R7 = 330 kOhms
R8 = 2.2 MΩ
R9 = 2, 2 kW
R10 = 39 kOhms
R11 = 100 kOhms
R12 = 470 kOhms
R13 = 100 kOhms
R14 = 5.6 kOhms
R15 = 390 kOhms
R16 = 100 kOhms
R17 = 100 kOhms
R18 = 4.7 kOhms
R19 = 33 kOhms
R20 = 10 Ω
R21 = 470 Ω 2 W
R22 = 330 Ω 2 W
P1 = 2.2 kOhms pot. lin.
C1 = 100 nF multilayer
C2 = 10 uF 16 V electrolytic
C3 = 22 nF polyester
C4 = 47 nF polyester
C5 = 16 uF 470 V
electrolytic
C6 = 100 nF multilayer
C7 = 100 nF multilayer
C8 = 1000 pF ceramic
C9 = 470 uF 63 V electrolytic
D1 = 1N4148 Diode
Diode D2 = 1N4148
D3 = Diode BYW80-200
T1 = BC547B NPN
T2 = BC557B PNP
U1 = LM339 Integrated
U2 = Built 4093
Regulator U3 = 7812
MSFT1 = MOSFET RFG75N06
Relay RL1 = 24V 2 10 RT A
CH1 = Inter. Key
P1 Pusher NF =
M = Motor 180 W 36 V DC
Misc:
2 Supports 2 x 7-pin
1 TO220 Heatsink
An isolation kit for TO3P
An isolation kit for TO220
An aluminum bar (radiator)
4 FASTON Terminals for it
A 2-pole terminal block
1 3-pole
The practical realization
Refer to Figures 4 and 5a. As for mounting the controller, we have provided a printed circuit board visible figures 3, 5a and 6. The realization of this circuit can be made by the traditional system of photo-or the revolutionary process (and convenient) of the "blue film" (see ELM 26, page 59 et seq.)
The assembly itself presents no particular difficulty.
For the development of two integrated circuits we used two supports and two terminals for external connections, one for the pot and the other for the activation circuit (key and push). For connection to the engine and battery pack, since the currents involved, we have identified four male contacts FASTON PCB. The voltage regulator has a double sink fins for TO220. The power MOSFET and the diode FAST will also be equipped with a sink: it is an aluminum bar that serves small dimensions for both (do not forget to insulate the back of these components with insulation kits correspondents).
To check the operation of the PWM controller is recommended, as a first step, not to mount the MOSFET and control with an oscilloscope to the output of T1/T2 pulses are actually present positive variable duty cycle.
Adjust trimmers R2 and R6 to obtain a linear excursion of the potentiometer, that is to say no pulse when the cursor is turned fully on one side and pulse duty cycle of almost 100% when the cursor is in opposite position.
Only then insert the IC and connect the motor (set it on your work bench to prevent it jumps!). Connect the power supply and verify that the speed of rotation depends on the position of the potentiometer.
The battery charger
The circuit diagram
See Figure 8. The second electronic circuit used for our scooter battery charger is intended, of course, to charge the group of batteries from the mains 220 V.
The circuit we have developed uses (for AC / DC conversion) a PWM system to do without power transformer.
With the DC voltage obtained we reload the batteries and we check, using a suitable circuit, the charge state: when the batteries are charged, the circuit stops charging.
In our installation, the load is within 1 to 1.5 A current and is complete after about 5 hours.
But look more closely at the circuit.
AC voltage 220 V rectifier RS1 reached by a double LC filter eliminating the risk of disruption of the sector by spurious signals of the switching circuit.
Downstream of the bridge rectifier is a filter capacitor across which a voltage of 300 V is present. This voltage feeds directly into the power stage MOSFET MSFT1 leading to the transformer primary and TF1 (points 3 and 4).
The integrated circuit U1, a simple TL3842, belong all the functions for the PWM stage. In practice, this integrated circuit oscillates at a frequency of 57 kHz and produces a pulse train whose duty cycle depends on the consumption of the powered circuit: the greater the consumption of the circuit, the longer the pulse duration.
To check the circuit power consumption, simply measure the voltage drops across the resistance of low value placed in series with the source of the MOSFET: the tension acts on the internal comparator controlling the PWM generator.
This floor has two other features: power to the chip on and off the circuit by an optocoupler. The supply voltage is obtained from the 300 V DC through two ballast resistor providing current relatively low, just enough to start the chip and trigger the oscillation. Then the circuit is powered by the voltage on the winding TF1 (points 1 and 2).
This voltage, rectified by diode D1 and filtered by C7, adds to the initial tension, providing proper nutrition to chip.
As for the optocoupler is a component that, when active, can almost completely inhibit the operation of the PWM, or to minimize the amplitude of pulses produced.
It is worth noting that the high voltage stage is galvanically isolated from the low voltage level through the use of the transformer TF1 and the optocoupler.
Explained is how the presence of two distinct masses with different symbols (Figure 8).
The pulses present on the secondary TF1 (winding points 5 and 7) are recovered by the double diode D6 FAST and made perfectly continuous with the LC filter with L2 and C13 are a part. Across the capacitor, we find a normal voltage of 45 V used to recharge the batteries and to power the control circuit using four operational amplifiers contained in U2, a banal LM324. The green LED LD1 indicates that its ignition voltage is present on the side and then the whole floor upstream is working properly.
The integrated circuit LM324 is powered by a stabilized voltage of 28 V provided by Zener DZ2.
Another zener (DZ 1) provides the reference voltage operational amplifiers to function as voltage comparators.
To check the battery charge is measured current they consume. To this end was placed in series with batteries, a low value resistor whose voltage drop is compared to the reference voltage. When the load current drops below 100 mA, the LED signal LD2-color changes from red to green to indicate the end of the load. This is not interrupted: the battery is maintained "buffering".
This circuit consists of operational amplifiers U2B and U2c while the other two operational amplifiers are there to see if the battery is connected or not to the output terminals or if they are short-circuited. In both latter cases, the optocoupler is activated to limit the operation of the PWM. By trimmers R25 and R29, it is possible to adjust the thresholds of the circuit. The same goes for U2d (controlling the action level of short circuit) it is possible to make some sort of adjustment by removing R15, increasing the threshold.
Figure 13a: TL3842 PWM Pin, seen from above.
Figure 13b: Pinout of the double diode fast STPR1620CT.
List of components Charger
R1 = 220 W 2 kOhms
R2 = 68 kOhms 1 / 2 W
R3 = 82 kOhms 1 / 2 W
R4 = 82 kOhms 1 / 2 W
R5 = 10 Ω
R6 = 33 Ω
R7 = 4.7 kOhms
R8 = 560 Ω
R9 = 0.33 Ω 5 W
R10 = 4.7 kOhms
R11 = 4.7 kOhms
R12 = 4.7 kOhms
R13 = 68 Ω
R14 = 560 Ω
R15 = 2.2 kOhms
R16 = 5.6 kOhms
R17 = 10 k
R18 = 39 kOhms
R19 = 1 k
R20 = 10 k
R21 = 2 kOhms 3.3 W
R22 = 10 k
R23 = 6.8 kOhms
R24 = 1.2 kOhms
R25 = 22 kOhms trimmer
R26 = 4.7 kOhms
R27 = 68 kOhms
R28 = 820 Ω
R29 = 22 kOhms
R30 = 10 k
R31 = 4.7 kOhms
R32 = .22 Ω 5W
R33 = 820 Ω
C1 = 100 nF 275 V pol.
C2 = 100 nF 275 V pol.
C3 = 470 pF 1 kV ceramic
C4 = 470 pF 1 kV ceramic
C5 = 47 uF 400 V electrolytic
C6 = 10 nF 1 kV ceramic
C7 = 100 uF 35 V electrolytic
C8 = 1000 pF ceramic
C9 = 5600 pF ceramic
C10 = 10,000 pF ceramic
C11 = 33 nF ceramic
C12 = 10 000 pF ceramic
C13 = 220 uF 63 V electrolytic
C14 = 100 uF 63 V electrolytic
C15 = 470 pF 1 kV ceramic
C16 = 47 uF 50 V electrolytic
C17 = 100 nF multilayer
C18 = 100 nF multilayer
C19 = 100 nF multilayer
D1 = 1N4007 Diode
Diode D2 = 1N4007
D3 = 1N4148 Diode
D4 = 1N4007 Diode
D5 = 1N4007 Diode
Diode D6 = STPR1620CT
D7 = 1N4007 Diode
D8 = 1N4007 Diode
= 5.6 V Zener DZ1 0.5 W
DZ2 = Zener 28 V 1 W
RS1 = 1N4007 Diode (4)
L1 = Self filtering area
10 uH L2 = 5 A
LD1 = LED 5 mm
Bicolor LED LD2 = 5 mm
FC1 = Optocoupler TLP627 or eq.
MOSFET IRF840 MSFT1 = o eq.
U1 = Integrated TL3842
U2 = LM324 Integrated
= Transformer TF1. (See text)
FUS1 = 2 A fuse
Misc:
1 Support 2 x 7-pin
1 Support 2 x 4-pin
1 Fuse holder for it
2 Radiators T0220
The practical realization
Refer to Figures 10 and 11.
From the practical point of view, the realization of the battery charger is not more difficult than that of cruise control. The only component to build oneself is the transformer ferrite whose dimensions bear a power of at least 80 to 100 W. All windings are made with enamelled copper wire of 0.3 to 0.4 mm in diameter.
The primary winding (points 3 and 4) requires 100 turns. Secondary (points 5 and 7) 25 turns and one that provides the voltage TL3842 (items 1 and 2) 8 turns. The power MOSFET and dual LED FAST are equipped with sinks.
To check the operation of the circuit, you must first defer the installation of LM324 with a multimeter and measure the presence of 300 V DC across the capacitor C5 and 40 to 50 V across the capacitor C13.
If you have an oscilloscope, you can also check the waveform present on the various points of high voltage circuit.
Then mount the LM324, connect in series to recharge the batteries and measure the voltage at their two extremes.
Adjust trimmers R25 and R29 so that up to 41.4 V (13.8 V x 3) LED signal changes from red to green.
Mechanical assembly of the drive and brake
Photos and drawings show the mechanical construction of the propulsion and braking of the scooter.
The chassis was made of welded properly profiled. In the center, we have provided housing for three batteries and PWM speed control. The most important section is the back part (14a and 14b) which are fixed on all elements of propulsion and braking. We used two wheels with tires chambers of 2.5 x 4 ", which is about 6 cm wide and 20 cm in diameter. The fork of the frame receives the axis of the rear wheel: it has a bearing allowing it to rotate freely. Two half-hubs attached to the wheel, one on each side, allow propulsion and braking. On the right half-hub is fixed a ring gear connected to the engine by a metal chain, the other demimoyeu receives a drum brake 80 mm including the static part is attached to the frame. On the same chassis, to 20 cm of the wheel, was mounted electric motor whose shaft is also equipped with a small ring gear to chain drive.
Figure 14a.
Figure 14b.
Figure 14: Mechanical assembly of the drive and brake.
List of components Charger
R1 = 220 W 2 kOhms
R2 = 68 kOhms 1 / 2 W
R3 = 82 kOhms 1 / 2 W
R4 = 82 kOhms 1 / 2 W
R5 = 10 Ω
R6 = 33 Ω
R7 = 4.7 kOhms
R8 = 560 Ω
R9 = 0.33 Ω 5 W
R10 = 4.7 kOhms
R11 = 4.7 kOhms
R12 = 4.7 kOhms
R13 = 68 Ω
R14 = 560 Ω
R15 = 2.2 kOhms
R16 = 5.6 kOhms
R17 = 10 k
R18 = 39 kOhms
R19 = 1 k
R20 = 10 k
R21 = 2 kOhms 3.3 W
R22 = 10 k
R23 = 6.8 kOhms
R24 = 1.2 kOhms
R25 = 22 kOhms trimmer
R26 = 4.7 kOhms
R27 = 68 kOhms
R28 = 820 Ω
R29 = 22 kOhms
R30 = 10 k
R31 = 4.7 kOhms
R32 = .22 Ω 5W
R33 = 820 Ω
C1 = 100 nF 275 V pol.
C2 = 100 nF 275 V pol.
C3 = 470 pF 1 kV ceramic
C4 = 470 pF 1 kV ceramic
C5 = 47 uF 400 V electrolytic
C6 = 10 nF 1 kV ceramic
C7 = 100 uF 35 V electrolytic
C8 = 1000 pF ceramic
C9 = 5600 pF ceramic
C10 = 10,000 pF ceramic
C11 = 33 nF ceramic
C12 = 10 000 pF ceramic
C13 = 220 uF 63 V electrolytic
C14 = 100 uF 63 V electrolytic
C15 = 470 pF 1 kV ceramic
C16 = 47 uF 50 V electrolytic
C17 = 100 nF multilayer
C18 = 100 nF multilayer
C19 = 100 nF multilayer
D1 = 1N4007 Diode
Diode D2 = 1N4007
D3 = 1N4148 Diode
D4 = 1N4007 Diode
D5 = 1N4007 Diode
Diode D6 = STPR1620CT
D7 = 1N4007 Diode
D8 = 1N4007 Diode
= 5.6 V Zener DZ1 0.5 W
DZ2 = Zener 28 V 1 W
RS1 = 1N4007 Diode (4)
L1 = Self filtering area
10 uH L2 = 5 A
LD1 = LED 5 mm
Bicolor LED LD2 = 5 mm
FC1 = Optocoupler TLP627 or eq.
MOSFET IRF840 MSFT1 = o eq.
U1 = Integrated TL3842
U2 = LM324 Integrated
= Transformer TF1. (See text)
FUS1 = 2 A fuse
Misc:
1 Support 2 x 7-pin
1 Support 2 x 4-pin
1 Fuse holder for it
2 Radiators T0220
The practical realization
Refer to Figures 10 and 11.
From the practical point of view, the realization of the battery charger is not more difficult than that of cruise control. The only component to build oneself is the transformer ferrite whose dimensions bear a power of at least 80 to 100 W. All windings are made with enamelled copper wire of 0.3 to 0.4 mm in diameter.
The primary winding (points 3 and 4) requires 100 turns. Secondary (points 5 and 7) 25 turns and one that provides the voltage TL3842 (items 1 and 2) 8 turns. The power MOSFET and dual LED FAST are equipped with sinks.
To check the operation of the circuit, you must first defer the installation of LM324 with a multimeter and measure the presence of 300 V DC across the capacitor C5 and 40 to 50 V across the capacitor C13.
If you have an oscilloscope, you can also check the waveform present on the various points of high voltage circuit.
Then mount the LM324, connect in series to recharge the batteries and measure the voltage at their two extremes.
Adjust trimmers R25 and R29 so that up to 41.4 V (13.8 V x 3) LED signal changes from red to green.
Mechanical assembly of the drive and brake
Photos and drawings show the mechanical construction of the propulsion and braking of the scooter.
The chassis was made of welded properly profiled. In the center, we have provided housing for three batteries and PWM speed control. The most important section is the back part (14a and 14b) which are fixed on all elements of propulsion and braking. We used two wheels with tires chambers of 2.5 x 4 ", which is about 6 cm wide and 20 cm in diameter. The fork of the frame receives the axis of the rear wheel: it has a bearing allowing it to rotate freely. Two half-hubs attached to the wheel, one on each side, allow propulsion and braking. On the right half-hub is fixed a ring gear connected to the engine by a metal chain, the other demimoyeu receives a drum brake 80 mm including the static part is attached to the frame. On the same chassis, to 20 cm of the wheel, was mounted electric motor whose shaft is also equipped with a small ring gear to chain drive.
Figure 14: Mechanical assembly of the drive and brake.
14c: The rotation of the motor shaft is transmitted to the rear wheel by chain. 
14d: On the opposite side is mounted a drum brake 80 mm fixed to the frame and half-hub.
The mechanical design of the scooter
Since we're done with the hardware, proceed to the realization of the mechanical part.
The framework was made and duly welded profiles.
The most important section is the back where all elements are fixed relative to the propulsion and braking.
Both wheels are 2.5 x 4 "(roughly 6 inches wide by 20 cm in diameter).
At the fork back of the chassis is fixed axis of the wheel: the wheel is rolling, it turns freely on this axis.
Two half-hubs set each side of the wheel handle propulsion (for ring gear and chain) and the brake (drum brake 80 mm fixed to the frame for the fixed and fixed to the hub for the half- moving part).
The engine is also attached to the frame, about 20 cm of the wheel. He also has a small ring gear secured to the tree, sending chain movement to the drive wheel.
All this is available commercially at a reasonable price, especially among dealers of spare cycles and motorcycles.
The handlebar may be that of an old moped and will be found to be scrapped. What happens on the handlebar brake cable to attach to the corresponding lever (do not forget to place the button below so that the engine has no power when you brake). On the other side of handlebar mount potentiometer (the "gas"!) With the handle adapted to be able to control the speed of rotation.
Place on the frame a solid platform and all will be adorned by a shroud made of wood or plastic.
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